This invention relates to an immunoagglutination measurement apparatus for quantifying antigens or antibodies by individually counting the particles of an agglutinate of an insoluble carrier produced by an antigen-antibody reaction.
Measurement of a tumor marker such as alpha-fetprotein (AFP) or carcinoembryonic antigen (CEA) has become extremely important in diagnosing cancers and in observing the progress of cancers.
Radioimmuno assay (RIA) and enzymeimmuno assay (EIA) methods are used in apparatus which measure immunity utilizing the antigen-antibody reaction. As is well known in the art, both methods enable highly sensitive measurement, but the RIA method requires troublesome waste treatment since radioactive substances are used, while the EIA method requires an extended period of time for measurements.
In order to solve these problems, an apparatus has been conceived in which antigen or antibody quantification is carried out by measuring, by a particle counting method, the degree of agglutination that accompanies a latex agglutination reaction utilizing the antigen-antibody reaction. An example is an immunoagglutination measurement apparatus available under the brandname PAMIA-10.
In accordance with this apparatus, a specimen containing an antigen or antibody to be measured is mixed with a reagent containing latex particles to which an antibody or an antigen is bonded that reacts specifically with the antigen or antibody in the specimen. As a result of mixing the specimen and the reagent, an antigen-antibody reaction takes place that causes the latex particles to coalesce together through the medium of the antigen or antibody in the specimen, thereby forming an agglutinate. The latex agglutinate is introduced into a flowcell where it is irradiated with light, the light scattered from the individual particles of the agglutinate is measured, the degree of agglutination is calculated from the number of non-agglutinated particles and the number of agglutinated particles distinguished from each other by measurement of the scattered light, and the degree of agglutination is converted into a figure representing the concentration of antigen or antibody in the specimen. In this way the antigen or antibody of interest within the specimen is quantified.
This conventional immunoagglutination measurement apparatus is in need of certain improvements.
(a) Owing to the sharp increase in the tumor markers to be examined, there is an increase in the amount of specimen and reagent required. A reduction in this amount is desired.
(b) Doubling of processing capability per unit time is strongly desired.
(c) An improvement in operability is required, namely efficient, accurate and safe operation in a small amount of space.
(d) Since mixing for the purpose of stabilizing and promoting the agglutination reaction is performed by rotating a rotor within a reaction vessel, the rotor sustains long-term wear and becomes unbalanced as a result. Thus there the risk of a decline in the mixing efficiency of the rotor.